Keywords:
Trauma, Athletic injuries, Structured reporting, Imaging sequences, Audit and standards, Plain radiographic studies, MR, Musculoskeletal system, Musculoskeletal joint, Bones
Authors:
C. Bishop, P. G. White; Torquay/UK
DOI:
10.26044/essr2019/P-0132
Imaging findings OR Procedure Details
Results:
Cartilage grading:
- Initial report: cartilage grade provided in 19 reports (38%)
- Of the 19: 13 numerical grading (a score based on the Outerbridge classification of patellar cartilage [2]),
6 written grading (mild / moderate / severe)
- Musculoskeletal radiology review agreed with the cartilage grade provided in 63%
- Overal there was improved agreement with increasing severity of grade
Figure 8 is a pie chart showing the variation in grade of OA found at musculoskeletal review in the study population.
A description of the cartilage was given in 14 reports (28%),
no grade was provided in these reports.
Words used included:
- Damage
- Thinning
- Irregularity
- Thickness loss
The MRI report contained a grade of degenerative changes (mild / moderate / severe) in 11 reports (22%).
A total of 11 reports (22%) had no mention of cartilage or degenerative changes.
Bone marrow oedema:
- Positive finding in the initial report in 11 cases (22%)
- Positive finding in the MSK radiology review in 20 cases (40%)
- 1 false positive,
10 false negatives
Subchondral cysts:
- Positive finding in the initial report in 5 cases (10%)
- Positive finding in the MSK radiology review in 10 cases (20%)
- 0 false positives,
5 false negatives
Review of cartilage and subchondral changes in OA on MRI and their correlation with a plain radiograph (Figures 2-8):
Mild OA (Figures 2 and 3): Multiplanar fat-saturated (FS) PD-weighted images in 58 year old patient with knee mechanical symptoms and pain which show some mild cartilage thinning in the medial tibiofemoral compartment (red arrows).
Moderate OA (Figures 4 and 5): Multiplanar FS PD-weighted images in a 60 year old patient with knee mechanical symptoms and pain which show near full thickness focal cartilage defects,
and a subchondral cyst and mild focal bone marrow oedema in the medial tibial condyle (red arrows).
Severe OA (Figures 6 to 8): Figures 6 and 7 are multiplanar FS PD-weighted images in a 70 year old patient with knee mechanical symptoms and pain which show diffuse full thickness cartilage loss in the medial tibiofemoral compartment,
subchondral cyst and bone marrow oedema in both the medial tibial and femoral condyles (red arrows).
Figure 8 shows a plain radiograph of the knee in the same patient,
which demonstrates medial compartment joint space reduction and small osteophytes.
The imaging findings in Figure 8 would be in keeping with moderate to severe OA,
however the MRI demonstrates that this is severe.
OA of the knee is almost always one grade worse on MRI than on plain radiograph.